Shiyi Chen

On-line identification of thermal process using a modified ts-type neuro-fuzzy system

In this paper, a modified TS-type neuro-fuzzy system (MTSNFS) for on-line identification is proposed, which possesses six layers of neurons to perform the fuzzy inference. A modified self-organizing competitive learning algorithm with capabilities of dynamical rules recruitment and cancellation is proposed for structure identification. A hybrid learning algorithm combining recursive least squares (RLS) estimation and ordered derivative learning is used for parameter estimation. Both the structure and parameters could be automatically determined online without a priori knowledge. Comparisons with other related works are made via identification of Box-Jenkins furnance. Identification of bed temperature of a circulating fluidized bed boiler using the MTSNFS is also presented in this paper. The results demonstrate that the proposed identification approach is of high accuracy and compactness, and suitable for on-line modeling and prediction.

Development of a simplified method for the determination of ampere-hour capacity of lead–acid battery

Selection of the optimum level of current for charging and discharging operations is an important factor for the performance of lead–acid batteries in PV application. Realizing this situation, an experimental study was carried out to determine the performance of battery under different charging and discharging current. The battery was charged at an input current of 6, 12, and 18 A, whereas under these input charging currents the battery was discharged at constant loads of 5.7, 11.4, and 17.1 A. Then algebraic equations for the determination of battery ampere-hour capacity, in relation with state of charge, were formulated with the help of MATLAB software. The proposed model provides the battery output directly without going through the calculation of constant unknowns and battery ampere-hour capacity. It is different from previous models, which only evaluate the battery ampere-hour capacities with the help of already calculated battery ampere-hour capacities and other battery parameters from the same battery. During the study, it was found that the rate of charge and discharge affected the duration of charge and discharge as well as battery ampere-hour capacity. When the rate is increased, the number of ampere hours was decreased along with the battery operational time duration. The developed model equations were validated with ours as well as other researcher’s measured values; the corresponding values were much closer when the values of state of charge were at the range of 100–90%. This study may be useful to understand the energy storage within a PV system and to select the optimum level of current, which consequently lengthens the life of the battery and improves the overall performance of a Photovoltaic panel (PV) system.

Reduction Behavior of Iron Oxide for Chemical-Looping Hydrogen Generation in a Compact Fluidized Fuel Reactor

Chemical-looping hydrogen generation (CLHG) integrates chemical-looping combustion (CLC) and the steam-iron process. It is a process for hydrogen production with inherent CO2 separation. CLHG includes three reactors: a fuel reactor, a steam reactor and an air reactor, with iron oxide as oxygen carrier. This paper presents a compact fluidized fuel reactor for CLHG to produce reductive FeO with CO2 sequestration. An iron ore as oxygen carrier was tested, and CO and syngas were used as fuels. The results showed that through this compact fuel reactor, reductive FeO for further hydrogen generation was obtained and a high concentration CO2 was separated at the outlet of the fuel reactor. The influence of riser temperature, bubble fluidized bed temperature and Fe2O3/CO ratio on the bed performance was investigated. It revealed that the bubble fluidized bed temperature and Fe2O3/CO ratio had a significant impact on the fuel conversion while the effect of riser temperature was marginal. The iron ore exhibited good reactivity and no agglomeration was found in the experiment.Copyright

Hydrodynamic Analysis of a Three-Fluidized Bed Reactor Cold Flow Model for Chemical Looping Hydrogen Generation: Pressure Characteristics

Chemical looping hydrogen generation (CLHG) can produce pure hydrogen with inherent separation of CO2 from fossils fuel. The process involves a metal oxide, as an oxygen carrier, such as iron oxide. The CLHG system consists of three reactors: a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). In the FR, the fuel gases react with iron oxides (hematite Fe2O3, magnetite Fe3O4, wustite FeO), generating reduced iron oxides (FeO or even Fe), and with full conversion of gaseous fuels, pure CO2 can be obtained after cooling the flue gas from the fuel reactor; in the SR, FeO and Fe reacts with steam to generate magnetite (Fe3O4) and H2, the latter representing the final target product of the process; in the AR, the magnetite is oxidized back to hematite which is used in another cycle.